Starting in version 7.16, this experimental functionality has been removed. You should use the journald input in Filebeat instead.
Logstash outputs remove
@metadata fields automatically. Therefore, if Logstash instances are chained directly or via some message
queue (for example, Redis or Kafka), the
@metadata field will not be available in the final Logstash instance.
@metadata fields, use the Logstash mutate filter with the rename setting to rename the fields to
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ELK for Logs & Metrics